Innate immunity is the first line of defense designed to protect the host from invading pathogens, including HIV. LIR investigators have previously demonstrated that natural killer (NK) cells, an important component of the innate immune response, produced a significant quantity of CC-chemokines that are known to suppress HIV replication through a non-cytolytic mechanism. LIR investigators have analyzed the ability of NK cells to suppress HIV replication from CD4+ T cells of HIV-infected individuals in vitro. Data suggest that the NK-mediated suppression can be potent and that it is related to the stage of HIV infection as well as the level of HIV plasma viremia. The study has revealed that HIV viremia impairs the ability of NK cells to scerete CC-chemokines and alters the expression of various inhibitory and chemokine receptors expressed on NK cells. Future studies will focus on elucidating the mechanisms of the suppression of HIV replication by NK cells, and the effect of HIV and HIV envelopes on the function of NK cells in vitro.